Internal-combustion engine



Nov. 13, 1928.

G. K. DAVOL INTERNAL COMBUSTION ENGINE Filed Aug. 26, 1921 v 5 FIG .I. N3

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V 'JtffirneyJ Patented Nov. 13,1928.

UNITED STATES PATENT OFFICE.

GEORGE K. DAVOL, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR TO CHARLES A.BROWN, OF HINSDALE, ILLINOIS.

INTERNAL-COMBUSTION ENGINE.

Application filed August 26, 1921, Serial No. 495,478.

My invention has largely to do with a means of stratifying the charge offuel and air in the cylinder of an internal combustion engine so that aquantity of air, in excess of thatwhich is required for combustion ofthe fuel, may be present Within the cylinder and yet be prevented fromcompletely mixing with the fuel, whether the fuel be liquid or gaseous.In an engine in which the ignition ofthe charge is accomplished by meansother than the heat of compression of the charge, it is necessary tohave at the point of ignition a mixture of fuel and air which isignit'able, or which possesses a certain proportion to air, or a certainfuel density, within limits. This requirement is ordinarily met byemploying a homogeneous mixture within the cylinder having approximatelythe same fuel density or ratio of fuel to air throughout its entiremass. At partial loads such an engine must have the quantity offreshcharge drawn 1nto the cylinder reduced, which is ordinarily done bythrottling the entire intake. This throttling of the vintake, reducingthe density of the charge drawn in to considerably less thanatmospheric, has for a number of well known reasons a very bad effect onthe efliciency of the engine.

My invention renders it practicable to have an internal combustionengine draw into its cylinder at all loads a full charge of air withoutthrottling, and to separately inject the fuel with or without additionalair in such a manner that it will not intimately mix with the whole ofthe charge of air before ignition. To accomplish this in an effectivemanner I employ a centrifugal action, or resort to the centrifugalstratification or segregation of 40 the charge, whereby the heavier fuelvapor liquid fuel in suspension,

or finely atomize of a whirling is thrown to the outer zones chargewhile the lighter portion of the mass comprising the more pure air isheld in the 5 center. Thisvprocedure is not intendedof course to effecta complete separation of fuel and air, and a certain necessary degree ofmixture will always take place as the princi leis carried out; but therewill exist'i-n the w irling mass, zones or strata having differ entratios of fuel to air, or different degrees offuel density, and certainof these zones or strata will provide the fueld'ensity proper forignition. x 65, This and other features of my invention of fuel over theplston 2.- This ring so held forms a combustion engineis shown at 1. Apiston 2 of which only the inner end is shown reciprocates within thecylinder and is shown in Figure 1 at the inner end of its stroke. Acylinder head 3 of which only a portion is shown in Figure 1 is securedto the cylinder in the usual manner. Main inlet and exhaust valves 4;and 5 respectively are indicated in Figure 1, seating in the head 3. I

The upper end of the cylinder is recessed or heavily counterbored,forming a short cylindrical chamber of larger diameter than the maincylinder bore, and in this enlarged bore is loosely held a ring 6. Thelower end of this ring 6- has an inwardly projecting flange 7 whichprojects as shown'in Figure 1 liner for the side walls of the cylinderclearance space or combustion chamber. At one side of this combustionchamber a bored openingis formed having two diameters and a shoulder 8,and through this opening the fuel injection nozzle 9 passes, being heldin place tight against the shoulder 8 by anysuitable means. The end ofthe nozzle passes also through an opening in the liner ringfi andextends slightly into the combustion chamher. The nozzle 9has a centralhole 10. connecting at the inner end of the nozzle. with the atomizingor injection orifice 11', Figure 2. This final injection-orifice isdirected tangentially with reference to the combustion .100 chamberwalls as shown clearly in Figure 2.

The fuel, gaseous or liquid, with or without 'admixtureof' air, issupplied through the passage 10 in the nozzles 9 from any suitablesource, at the proper periods and at suitable pressure, and issuing in atangential direction, indicated in Fig. 2, whirls around the cylindricalcombustion chamber and imparts to most of the charge of air therein thewhirling motion indicated by the arrows in 1'10 Figure 2. In thiswhirling movement it mixes to a greater or less extent with the aircharge, but owing to the fuel, whether a vapor or a finely atomizedliquid, being heavier than the air, there will be a strong tendency andaction to concentrate the fuel toward the outer strata or zones of themass next\to the inner face of the liner ring 6.

If a gas lighter than air be used as fuel, this action will notlogically take place, and the invention is intended to be applied to theuse of gaseous fuels or vapors heavier than air, and to finely atomizedliquids or pulverized solid fuel.

The degree to which the injected fuel mixes with the contained aircharge may be controlled in a number of ways, as for example by varyingthe exact direction of the entering jet, or by obstructions projectinginto the chamber from its walls such as the obstruction formed by theprojecting end of the spark plug 12 or by modifying the form of thepiston end so that it may fill more of the center portion of thecombustion chamber and crowd the air charge closer to the side walls. Inthese ways a suflicient degree of mixture of the injected fuel with theair charge can be insured so that the heavier fuel charges will readilyfind sufficient air to afford proper combustion; while at the same timea rich mixture or a strata of high fuel density is insured adjacent tothe side Walls of the chamber even with light fuel injections for lightloads.

If a spark plug be so located that the spark gap is close to the sidewalls of the combustion chamber or close to the inner face of the linerring 6 the spark will always be formed in'the zone or strata ofthegreatest fuel density.

It is logically conceivable that the extreme outer strata next the sidewalls might contain under some conditions and arrangements, too greatafuel density to be readily ignitable and on this account the location ofthe spark gap or other 'ignitingz'means might more advantageously. beplaced further inward toward the centerjof the chamber, where lessdensity of fuel would exist.

- It may be found with certain conditions of arrangement of the chamber,and in engines whlch are called upon for great variation in output, thatno one location of the spark gap or other igniting meanswill ive thebest results under all conditions of 11 ht and heavy loads, with largeand small in ections of fuel, and to meet such extreme differences ofloading my invention provides for the use of more than one spark gap orother igniting means, each spark gap being placed in a dlflerentcentrifugal strata or a centrifugal zone of different fuel density. Inother words two. spark gaps may for example be used, one spark the sidewall of the chamber and one being placed well within the chamber orcloser gap being located close to to its axis. With such arrangementeach spark gap will be in a different annular zone or stratum, or eachspark gap will occupy a position in a zone or stratum of a fhel densitydiffering from that of the other. In this manner although a greatvariation in the fuel density, or fuel content of all strata or zonesmay occur, one of the spark gaps will always be in a position where anignitable mixture exists.

In the drawings I have shown provision for two spark gaps, one close tothe side wall of the combustion chamber and one placed well within thechamber. I have there shown the spark gaps arranged in series, so thatthe electrical discharge jumps two gaps one after the other in the samecircuit. This arrangement it will be understood is not at all essentialbut merely forms a convenient manner of arranging for two points ofignition. Two I point 17 is fixed to the outer shell of the plug and isbrought close to the sleeve 15. It can now be seen that two spark gapsin-series are provided one at 18 well within the combustion chamber andone at 19' close to the side wall. These spark gaps are in zones orstrata of different fuel densities.

The liner ring 6 is employed to form aheated surface on which theinjected fuel impinges afternissuing from the atomizing orifice. Thisring 6 is not closely in contact with the surrounding walls of thecylinder, but has a suitable clearance from such surfaces and is heldfrom close contact by small rojections suitably placed and proportioneg.Inthis manner flow of heat from the ring 6 to the water jacketedcylinder ,walls is properly obstructed, with the effect that the'ringattains a higher temperature than the water acketed cylinder walls. 7 p

The inwardly projectin flange 7 on the ring 6 .is intended to catc anyliquid fuel WlllCll, particularly under starting conditions when allsurfaces are cold, may escape com bustion and run down the'inside faceof the ring. Such liquid fuel if allowed to reach the main bore of thecylinder has a tendenc to work by the piston and into the crank chamberbelow, contaminating or diluting the lubricating oil on cylinder wallsand in crank case. The inwardly projecting flange 7 catches and holdsany such liquid fuel for a time and before any can reach the maincylinder bore it must collect and overrun the inside upwardly projectinglip of the flange 7. This inner li of the flange being of relativelythin section, rapidly becomes hot on starting the engine, and ismaintained at a high temperature, and any liquid fuel coming intocontact with it is rapidly vaporized and burned away and so cannot reachthe main cylinder bore below.

The inside face of the liner ring 6 is shown in the drawings as a smoothsurface, but it may, if desired to give it an increased heating orvaporizing eflect for certain fuels or conditions of operation, beprovided with inwardly projecting flanges, or pins, or projections, toincrease its vaporizing surface or its mechanical mixing effect.

In referring herein to strata or zones of differing fuel densities, itis of course not in-. tended to imply that any given annular stratum-orzone is sharply defined from an adjacent stratum by difference of fuelcontent but that the average fuel density of any given stratum or zonedoes differ from that of an adjacent one.

In the claims which follow I have used the term circular section indefining the form of the combustion chamber and this chamber of circularsection is the simplest form and the form I prefer. It is, however,perfectly obvious that a departure from the truly circular form,producing a section more or less oval or elliptical, will not sensiblyaffect the action sought and the expression circular section is intendedto cover such slight deviations from the truly mathematical circularfrom.

Without further elaboration, the foregoing will so fully explain thegist of my invencombustion engine consisting tion that others may byapplying current knowledge, readily adapt the same for use under variousconditions of service, without eliminating certain features which mayproperly be said to constitute the essential items of novelty involved;which items are intended to be defined and secured to me by thefollowing claims.

I claim:

1. The method of operating an internal of stratifying or segregating acharge of fuel and air within a combustion chamber by centrifugal actioninto zones or strata of different fuel densities and igniting the chargeat points of diflerent fuel densities.

2. The method of operating an internal combustion engine consisting ofwhirling or rotating a charge of fuel and air within a combustionchamber about an axis, and igniting the charge at a plurality of pointsat different distances from said axis.

8. The method of operating an internal combustion engine which consistsof compressing a charge within a combustion chamber, injecting fuelthereinto in a manner to set up a circumferential whirling or rotationof the charge and igniting thecharge at points of different fueldensities.

4. The method of operating an internal combustion engine which consistsof injecting a fuel into a charge compressed within a combustionchamber, stratifying or segregatingv the charge by centrifugal actioninto cylindrical strata or zones of different fuel densities andigniting the charge at points of different fuel densities.

5. In an internal combustion engine, a combustion chamber, means forwhirling the charge in the said chamber to stratify it, thermallyisolated means encircling the periphery of the said chamber and meansfor igniting the charge at points of different fuel densities. I

6. In an internal combustion engine, a combustion chamber, means forwhirling the charge in the said chamber to stratify the charge intozones of different fuel densities, thermally isolated means ofappreciable heat capacity and good conductivity encircling the peripheryof the said chamber, and means for igniting the charge at points ofdifferent fuel densities.

7. In an internal combustion engine, a working cylinder, a combustionchamber, means for supplying a charge of fuel to the said chamber, meanspositioned within the combustion chamber for preventing the fuel fromseeping into the lower parts of the working cylinder and means forigniting the. charge at points of different fuel densities.

8. In an internal combustion engine, a working cylinder, a combustion.chamber, means for supplying a charge to the said chamber, a thermallyisolated sleeve positioned within the said combustion chamber, a troughformed on the said sleeve for preventing the fuel from seeping into thelower parts of the working cylinder, and means for igniting the chargeat points of different fuel densities.

In witness whereof, Lhereunto subscribe my name this 23rd da of August,1921.

GEgRGE K. DAVOL.

